Microstructural Evolution in Aluminum Alloy 7050 during Cooling from Homogenization

Microstructure of post-homogenization is significant to prevent particle stimulated nucleation of recrystallization. This paper investigated microstructure evolution in alloy 7050 during cooling from homogenization. Two intermetallic phases, Al7Cu2Fe and Mg2Si were insoluble during homogenization. Cooling to 460 °C and 400 °C follow by quenching, precipitates nucleated discontinuously on the grain boundaries, no precipitates was found within the grains. The precipitates were found near the grain boundaries when quenching from 350 °C, and precipitated uniformly within the center of the grains when quenching from 250 °C. The sizes of the precipitates increased with the decreased of the quenching temperature. Controlling of the post-homogenization microstructure is beneficial to prevent particle stimulated nucleation of recrystallization.